// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CC_TREES_SWAP_PROMISE_MANAGER_H_
#define CC_TREES_SWAP_PROMISE_MANAGER_H_

#include <set>
#include <vector>

#include "base/macros.h"
#include "cc/base/cc_export.h"
#include "cc/output/swap_promise.h"

namespace cc {
class SwapPromise;
class SwapPromiseMonitor;

class CC_EXPORT SwapPromiseManager {
public:
    SwapPromiseManager();
    ~SwapPromiseManager();

    // Call this function when you expect there to be a swap buffer.
    // See swap_promise.h for how to use SwapPromise.
    void QueueSwapPromise(std::unique_ptr<SwapPromise> swap_promise);

    // When a SwapPromiseMonitor is created on the main thread, it calls
    // InsertSwapPromiseMonitor() to register itself with LayerTreeHost.
    // When the monitor is destroyed, it calls RemoveSwapPromiseMonitor()
    // to unregister itself.
    void InsertSwapPromiseMonitor(SwapPromiseMonitor* monitor);
    void RemoveSwapPromiseMonitor(SwapPromiseMonitor* monitor);

    // Called when a commit request is made on the LayerTreeHost.
    void NotifySwapPromiseMonitorsOfSetNeedsCommit();

    // Called before the commit of the main thread state will be started.
    void WillCommit();

    // The current swap promise list is moved to the caller.
    std::vector<std::unique_ptr<SwapPromise>> TakeSwapPromises();

    // Breaks the currently queued swap promises with the specified reason.
    void BreakSwapPromises(SwapPromise::DidNotSwapReason reason);

    size_t num_queued_swap_promises() const { return swap_promise_list_.size(); }

private:
    std::vector<std::unique_ptr<SwapPromise>> swap_promise_list_;
    std::set<SwapPromiseMonitor*> swap_promise_monitors_;

    DISALLOW_COPY_AND_ASSIGN(SwapPromiseManager);
};

} // namespace cc

#endif // CC_TREES_SWAP_PROMISE_MANAGER_H_
